Fluorinated glycidyl ethers and use thereof

ABSTRACT

FLUOROALKYL GLYCIDYL ETHERS ARE PREPARED BY REACTING A FLUOROKETONE WITH AN ALKALI METAL FLUORIDE, THEN REACTING THE RESULTING INTERMEDIATE WITH AN EPIHLOHYDRIN. TYPICALLY, THE KETONE IS HEXAFLUOROACETONE WHEREBY THE END PRODUCT IS HEPTAFLUOROISOPROPYL GLYCIDYL ETHER. THE GLYCIDYL ETHERS ARE USEFUL, IN MONOMERIC AND ESPECIALLY POLYMERIC FORM, FOR IMPARTING WATER-AND OIL-REPELLENCY TO TEXTILES.

United States Patent 3,766,219 FLUORINATED GLYCIDYL ETHERS AND USETHEREOF Allen G. Pittman, El Cerrito, and William L. Wasley,

Berkeley, Calif., assignors to the United States of America asrepresented by the Secretary of Agriculture No Drawing. Application July26, 1967, Ser. No. 666,530, which is a division of application Ser. No.421,128, Dec. 24, 1964. Divided and this application Jan. 16, 1970, Ser.No. 3,513 The portion of the term of the patent subsequent to Jan. 2,1985, has been disclaimed Int. Cl. C07d 1/18 US. Cl. 260--348 R 3 ClaimsABSTRACT OF THE DISCLOSURE Fluoroalkyl glycidyl ethers are prepared byreacting a fluoroketone with an alkali metal fluoride, then reacting theresulting intermediate with an epihalohydrin. Typically, the ketone ishexafluoroacetone whereby the end prodnot is heptafluoroisopropylglycidyl ether. The glycidyl ethers are useful, in monomeric andespecially polymeric form, for imparting waterand oil-repellency totextiles.

This is a division of our copending application, Ser. No. 666,530, filedJuly 26, 1967, now Pat. 3,504,000, which in turn is a division of Ser.No. 421,128, filed Dec. 24, 1964, now Pat. 3,361,685.

A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to and has among its objects the provision ofnovel processes for preparing fluorinated compounds, particularlyfluorinated glycidyl ethers and polymers thereof; the provision of thecompounds as new compositions of matter; and procedures for treatingfibrous materials, especially textiles, with the compounds. Furtherobjects of the invention will be evident from the following descriptionwherein parts and percentages are by weight unless otherwise specified.

The symbol Gly is used herein to designate the glycidyl radical:

In conventional practice if it is desired to convert a ketone into aglycidyl ether, the following procedure is used: The ketone is reducedto an alcohol and the alcohol 3,766,219 Patented Oct. 16, 1973 isetherified with an epihalohydrin, e.g., epichlorohydrin orepibromohydrin. Thus:

I NaBH4 I HO OH eplhalohydrln 0:4) l MO-liJ-F In the above formula Mstands for an alkali metal. (Note: No novelty is claimed herein for thisfirst step per se; it is disclosed and claimed in our prior application,Ser. No. 398,129, filed Sept. 21, 1964.)

In a second step, the fiuorocarbinolate intermediate is reacted with anepihalohydrin (e.g., epichlorohydrin, epibromohydrin, or epiodohydrin)to form a glycidyl ether, as follows:

epibrornohydrin By this simple two-step synthesis, many different kindsof fluorinated glycidyl ethers can be produced in yields as high as ofthe theoretical. The reactions may be further exemplified by thefollowing formulas, which depict the synthesis of heptafluoroisopropylglycidyl ether from hexafluoroacetone:

It is evident from the above formulas that the synthesis converts theketone function to an ether function without requiring the use of areducing agent and concomitantly a fluorine group is added, that is, theglycidyl ether contains a fluorine group on the alpha carbon atom of thealcohol moiety. This is an unusual and heretofore unknown type ofstructure which gives the products especially useful properties. Forexample, the products can be used to provide oil-, water-, andsoil-repellent finishes on textiles and the repellency attained issubstantially greater than that achieved with the correspondingcompounds wherein the same position is occupied by hydrogen.

The process of the invention is by no means limited to the example abovebut is of great versatility and, generically, can be applied to anyaliphatic (one-chain or closedchain) ketone which contains at least twofluorine groups adjacent to the carbonyl group. In other words, thecarbon atoms connected to the carbonyl group must contain at least twofluorine atoms-distributed on these carbon atoms symmetrically orasymmetrically. These fluorine groups are a critical item to activatethe carbonyl group so that it will undergo the desired transformationwhen contacted with the alkali metal fluoride. Especially good resultsare obtained when the carbon atoms adjacent to the carbonyl radicalcontain halogen radicals (i.e., F, Cl, Br, or I) in addition to theminimum of two fluorine groups. In this connection it may be noted thatalthough halogens of higher atomic weight than fluorine-Le, Cl, Br, andIare not effective by themselves to activate the carbonyl group, theycan be employed to supplement the activating influence of fluorinegroups. Beyond the positions adjacent to the carbonyl group, thestructure of the ketone is of no criticality to the process andavailable sites may be occupied, for example, by hydrogen or halogen. Inother words, the critical item for the process aspect of this inventionis that the starting compound contain a carbonyl group activated byadjacent fluorine atoms as explained hereinabove; the remainder of thestarting compound is not material to the process. Of course, thisremainder may be limited in accordance with certain parameters toprovide particular desired characteristics in the glycidyl etherproducts. However, such limitation concerns the character of theglycidyl ether product, not the operation of the process.

Typical examples of ketones to which the process of the invention may beapplied and the corresponding ether products are given below by way ofillustration but not limitation. As noted above, the symbol Gly standsfor the glycidyl radical Gly-O Whercin n is a number from to 18 WhoreinR represents the heptafluorocyclobutyl radical Wherein n is a numberfrom 3 to 10 Compounds Containing Other Halogen Atoms in Addition toFluorine (Y is Cl, Br, or I) Gly-O Gly-O Gly-O wherein n is a numberfrom 0 to 18 wherein n is a number from 0 to 18 Compounds ContainingHydrogen in Addition to Fluorine (n and n are each a number from 1 to18) Gly-O Wherein R represents an alkyl group containing 1 to 18 carbonatoms or a cycloalkyl group such as cycloprcpyl, cyclobutyl, orcyclohexyl It is also within the broad scope of the invention toutilize, as the starting material, ketones containing more than onecarbonyl group. By adjustment of the proportions of reactants in linewith usual stoichiometrical relationships, diethers are produced.Typical in this category are the following:

ature for convenience but it does take place at much lower temperatures.Where the starting ketone is a gas -Gly Generically, a preferred classof ketones which may be used in the process of the invention and theintermediates and the glycidyl ethers formed therefrom may berepresented by the following structures:

(B) Alkali metalfiuoro- (C) Glycidyl (A) Ketone carblnolate ether R I RR-t'J-R R-C-R R--( J-R O=I MO-CF Gly-OOF RCR R-C-R R R I I R R R Whereineach R represents amember of the group consisting of hydrogen halogen,alkyl, haloalkyl, cycloalkyl, an halocycloalkyl and wherein at least twoof the Rs are fluorine. M represents an alkali metal.

The glycidyl ethers responding to the structure given above in Column Care new compounds, not heretofore prepared or described. Another groupof new compounds are the cyclic glycidyl ethers, e.g., those respondingto the formula where n is a number from 3 to 10, which may be preparedfrom the corresponding cyclic ketones CFaCl Gly-O-CF As noted above, inthe first step of the synthesis the fluoroketone is reacted with analkali metal fluoride. As the latter reagent, potassium fluoride isgenerally preferred, but the fluorides of sodium, cesium, and rubidiummay also be used. The reaction is generally conducted in an inertsolvent for the ketone, for example, acetonitrile, dioxane,tetrahydrofuran, tetramethylene sulphone, diglyme (an abbreviated namefor dimethyl ether of diethylene glycol), etc. The alkali metal fluorideis only slightly soluble in these solvents and the disappearance ofundispersed alkali metal fluoride during the reaction supplies a usefulindication of formation of the desired intermediate (which is soluble).The temperature of reaction is not critical. Generally, temperaturesover 35 C. are avoided to prevent decomposition of the intermediate.Usually, the reaction is conducted at room temper- (for example,hexafiuoroacetone) it is preferred to cool 5 the system first to get theketone into solution. Then,

the temperature can be increased-for example, allowed to warm to roomtemperatureto accelerate the reaction. To prevent hydrolysis of theintermediate, the reaction is conducted under anhydrous conditions. Itis also helpful to remove air (which may contain moisture) by flushingthe reaction vessel with dry, inert gas such as nitrogen. When theintermediate is formed-as evidenced by disappearance of undissolvedalkali metal fluoridethe system is ready for further treatment.Generally, the intermediate is not isolated but is employed just as itis formed. The etherification is accomplished simply by adding theepihalohydrin (i.e., epichlorohydrin, epibromohydrin, or epiiodohydrin)to the reaction system containing the intermediate and stirring themixture. The temperature at which the etherification is conducted is nota critical factor and may vary, for example, from 20 to C. Generally,the higher temperatures in this range, namely about 50 to 100 C., arepreferred to increase the rate of reaction.

The glycidyl ether is recovered from the reaction system in thefollowing manner: The precipitated inorganic halide (for example,potassium bromide where the reactants are epibromohydrin and a potassiumfluorocarbinolate) is removed and water is added to the reactionmixture. The organic phase containing the glycidyl ether is removed fromthe aqueous phase and is then dried and the product separated bydistillation. In the alternative, the reaction mixture may be filteredto remove alkali metal salt and the product isolated by distillation.

The glycidyl ethers produced in accordance with the invention may beused in many areas wherein epoxides in general are employed, e.g., asintermediates in reactions involving the oxirane ring. Moreover, theglycidyl ethers are polymerizable and can be formed into homopolymers orcopolymers by standard techniques used in the polymerization ofepoxides. Homopolymers can be produced, for example, by mixing theglycidyl ether with a catalytic quantity of a Lewis acid such as borontrifluoride or ferric chloride or boron trifluoride-etherate. Copolymerscan be produced by applying the same procedure to a mixture of theglycidyl ether plus a different epoxide monomer such as ethylene oxide,propylene oxide, epichlorohydrin, phenyl glycidyl ether, styrene oxide,or the like. High molecular weight, solid polymers can be obtained byheating the monomers at 70-80 C. with a small amount of a diethylzinc/water catalyst system. These polymers are highly elastic materialswhich are useful in the preparation of rubbers which are to be used atextremes of low and high temperatures and/or under conditions whereresistance to ordinary solvents is required. They can be employed insuch applications as coating and as adhesives in laminating sheetmaterials. Of special interest is that these high molecular weight,solid polymers exhibit low solubility in common solvents such asbenzene, toluene, xylene, etc., whereas they are soluble in fluorinatedsolvents such as benzotrifluoride, 1,3-bis-trifluoromethyl benzene, andthe like. Thus, the polymers in question can be used in coating andadhesive applications where other polymeric materials are unsuitablebecause of solubility in common organic solvents.

A particular phase of the present invention is concerned with thetreatment of fibrous materials, such as textiles, in order to improvetheir properties, e.g., to improve their oil-, water-, andsoil-repellency. In practicing this phase of the invention, a glycidylether is prepared as hereinabove described and is applied to the fibrousmaterial, using either of two procedures. In one procedure, themonomeric glycidyl ether is applied to the fibrous material andpolymerized in situ thereon by applying a conventional epoxidepolymerization catalyst such as an acidic or basic catalyst system (HCl,BF triethylamine, etc.) This procedure can lead to a polymer which isgrafted to the fiber molecules when the fibrous material contains groupssuch as carboxyl, hydroxyl, or amino which react with and form covalentlinkages by reaction with the oxirane ring systems. Typical of suchfibrous materials are wool, viscose rayons, cotton, paper, and the like.In a typical application of this procedure, the fibrous substrate suchas wool cloth is padded through a methanol solution containing 5 to 40%of the glycidyl ether and (based on weight of the glycidyl ether) ofzinc fluoborate catalyst to an 80- 100% wet pick-up. The fabric is thendried and cured for 5-10 minutes at 100-125 C. In a preferred embodimentof the invention, the glycidyl ether is first polymerized and thenapplied to the fibrous material. The polymer may be a homopolymer, thatis, one consisting of recurring units of the glycidyl ether, or it maybe a copolymer, that is, a polymer containing recurring units of theglycidyl ether interspersed with units derived from a different epoxidemonomer, such as styrene oxide, propylene oxide, ethylene oxide,epichlorohydrin, phenyl glycidyl ether and the like. The polymers areprepared by conventional techniques. For example, the glycidyl ether perse or admixed with a different epoxide monomer is heated at about 70- 80C. in the presence of a small amount of diethyl zinc/ water. Asillustrative examples of this procedure, when heptafluoroisopropylglycidyl ether is formed into a homopolymer, the product is a polymercontaining in its skeletal chain recurring units of the structure:

In the event that the same glycidyl ether is copolymerized withpropylene oxide, for example, the copolymer product contains in itsskeletal chain recurring units of the above type plus recurring unitsderived from propylene oxide, i.e.

In any event, the polymers (homoor co-polymers) are applied to thefibrous material in conventional manner. Typically, the polymer isdissolved in an inert, volatile solvent--for example, benzotrifiuorideor 1,3-bistrifiuoromethyl benzene-and the resulting solution applied tothe fibrous material by a conventional dip and pad technique. By varyingthe concentration of polymer in solution and the degree of padding, theamount of polymer deposited on the material may be varied. Typically,the amount of polymer may be about from 0.1 to 20%, based on the weightof fibrous material but it is obvious that higher or lower proportionscan be used if desired. Usually, in treating textiles such as fabricsthe amount of polymer is limited to about 0.1 to 10% to attain thedesired repellency improvement without interference with the hand of thetextile. Generally, it is preferred to subject the fibrous material to aconventional curing operation after application of the polymer solutionthereto in order to bond the polymer to the fibers. As an example ofsuch treatment, the fibrous material is heated to the range of about 50to 150 C. for a period of about 5 to 30 minutes. The solvent (from thepolymer solution) may be evaporated in a separate step prior to curingor may be simply evaporated during the curing operation. In analternative procedure, the polymers are applied to the fibrous materialin the form of an aqueous solution, then curing is applied. Fibrousmaterials treated with the polymers of the invention display anincreased resistance to becoming soiled because they repel both waterandoil-borne soils and stains. Moreover, the improvements so rendered aredurablethey are retained despite laundering and dry-cleaning of theproduct. Especially good results (durability of the imparted repellency)are attained where the fibrous material contains groups such ashydroxyl, carboxyl, amino, etc. (as is the case with wool, cotton,viscose rayons, and other hydrogen-donor fibers) whereby the appliedpolymer is chemically bonded (grafted) to the fiber molecules.

The invention may be utilized for improving the properties of all typesof fibrous materials, for example, paper, cotton; linen; hemp; jute;ramie; sisal; cellulose acetate rayons; cellulose acetate-butyraterayons; saponified acetate rayons; viscose rayons; cuprammonium rayons;ethyl cellulose; fibers prepared from amylose, algins, or pectins; wool;silk; animal hair; mohair; leather; fur; regenerated protein fibersprepared from casein, soybean, peanut proteins, zein, gluten, eggalbumin, collagen, or keratins; nylon; polyurethane fibers; polyesterfibers such as polyethylene terephthalate; polyacrylonitrile-basedfibers; or fibers of inorganic origin such as asbestos, glass, etc. Theinvention may be applied to textile materials which are in the form ofbulk fibers, filaments, yarns, threads, slivers, roving, top, webbing,cord, tape, woven or knitted fabrics, felts or other non-woven fabrics,garments or garment parts.

EXAMPLES The invention is further demonstrated by the followingillustrative examples. The various tests described in the examples werecarried out as described below:

Oil repellency: The 3M oil repellency test described by Grajeck andPetersen. Textile Research Journal, 32, pages 320-331, 1962. Ratings arefrom 0 to 150, with the higher values signifying the greater resistanceto oil penetration.

Water repellency: AATC spray test, method 22-1952. Ratings are from 0 to100, with the higher values signifying greater resistance to waterpenetration.

Example IF-Preparation of heptafiuoroisopropyl glycidyl ether A dry,250-ml., three-neck flask was fitted with a Dry- Ice reflux condenser,gas-inlet tube, and magnetic stirring bar. Eight and eight-tenths grams(0.15 mole) dry potassium fluoride was placed in the flask, followed by70 cc. diglyme. This dispersion was cooled to minus 40 C., by applying aDry-Ice cooling bath to the flask. Twenty-six grams (0.15 mole) ofhexa-fiuoroacetone was introduced into the flask. The cooling bath wasthen removed and the system allowed to come to room temperature. As thesystem warmed, formation of the fiuorocarbinolate intermediate wasevidenced by disappearance of the dispersed KF, giving a homogeneoussolution.

Then, 20.5 grams (0.15 mole) of epibromohydrin was added in one batch.The Dry-Ice condenser was replaced with a water condenser and thereaction mixture was heated for 10 hours at -90 C. The solid precipitateof potassium bromide (30 g.) was then removed by filtration and thefiltrate poured into 200 cc. of cold water. The lower (fluorocarbon)layer was removed and washed three times with 50-cc. portions of water.Thirty grams (80% yield) of crude product was obtained. This product waspurified by fractional distillation, yielding 18 grams 9 of the pureglycidyl ether, B.P. 1171l8 C. at 760 mm; N 1.3169.

Calculated for C F H O (percent): C, 29.75%; F, 54.96; H, 2.06. Found(percent): C, 29.69; F, 54.87; H, 2.01. Calculated M.W. 242. Found (HBrtitration): 240. The infrared and NMR spectra were in accordance withthe structure given above.

Example II.-Preparation of fi-chlorohexatluoroisopropyl glycidyl etherCFzOl oQon-Cm-o-d F Fa Using the procedure described in Example I, thefollowing materials were applied to the reaction:

Cesium fluoride grams 22.8 Diglyme (solvent) cc..- 70Monochloropentafluoroacetone grams 29 Epibromohydrin do 20.5

The glycidyl ether was obtained in a 62% yield, B.P. 139.5-140 C./760mm., N 1.3634.

Example III.Preparation of fi,fl'-dichloropentafluoroisopropyl glycidylether CFzCl CHr-CH-CHz-O- F Using the procedure described in Example I,the following materials were applied to the reaction:

Potassium fluoride grams 5.9 Diglyme (solvent) cc 70Sym.-dichlorotetrafluoroacetone grams 27 Epibromohydrin do 13.7

The glycidyl ether was obtained in a yield of 66%, B.P. 170-172 C./760mm.

Example IV.-Polymerization of heptafluoroisopropyl glycidyl ether withdiethyl zinc/H O A 7-mm. (inner diameter) Pyrex glass tubing, sealed atone end was placed on a manifold system and evacuated. The glass tubewas placed in a Dry-Ice-acetone bath and 1.5 gm. of heptafluoroisopropylglycidyl ether was introduced followed by 4 10- mole of water, 6 10 moleof diethyl zinc and finally l-cc. of dry cyclohexane. The glass tubingwas then melt sealed, positioned on a wristaction shaker and heated at70 C. in a water bath for 20 hours. The solid polymer plug was removedfrom the tube and heated in a vacuum oven at 80 C. for 24 hours toremove residual solvent and monomer. An 80% conversion to a highlyelastic solid polymer had been obtained. A 1% solution of the polymer inbenzotrifiuoride gave an inherent viscosity of 0.5 at 25 C.Difi'erential thermal analysis (DTA) of the polymer revealed anendothermic reaction at ca. 43 C. which presumably is the glasstransition temperature and thermal decomposition beginning about 270 C.

Solubility of the polymer was tested by placing a small amount ofpolymer in a screw capvial containing solvent and shaking for 15 hoursat 25 C. Under these conditions the polymer readily dissolved inbenzotrifluoride but did not dissolve or appear to swell in benzene,p-dioxane or N,N-dimethylformamide.

Example V.--Polyrnerization of heptafluoroisopropyl glycidyl ether withBF -etherate Ten parts of heptafluoroisopropyl glycidyl ether was placedin a glass tube and cooled in a Dry Ice-acetone bath. Then, one part ofboron trifluoride ethereate was added and the tube sealed and allowed towarm to ambient temperature. As the system reached room temperature itwas observed that a vigorous exothermic reaction was taking place. Thesystem was heated for 20 hours at 70 C. and the product subjected tovacuum to remove residual monomer boron trifluoride and ether. Theproduct was a viscous liquid polymer, obtained in an amount representingca. 60% conversion of the monomer to polymer. It was soluble in a widevariety of organic solvents, including acetone, toluene,dimethylformamide, diglyme, etc.

Example VI.-Polymerization of fi-chlorohexafiuoroisopropyl glycidylether This glycidyl ether polymerized in the same manner as described inExamples IV and V. For instance, a sealed tube polymerization of,8-chlorohexafluoroisopropyl glycidyl ether using 10% BF /diethyl etheras catalyst gave a 72% conversion to a viscous liquid polymer soluble ina wide range of organic solvents.

Example VII.-Application of poly-(heptafiuoroisopropyl glycidyl ether towool fabric The elastomeric solid polymer described in Example IV wasdissolved in benzotrifluoride. Solutions containing from 0.4 to 10% ofthe polymer were prepared. Wool swatches were immersed in the polymersolution, squeezed to obtain ca. wet pick-up, dried and cured at C. for15 minutes. Oil and water repellency ratings are given below for thetreated fabrics:

Wt. percent of resin Oil repel- Water repelon fabric lency rating lencyrating 60 100 Control, untreated 0 50 Having thus described theinvention, we claim: 1. A process for preparing a glycidyl ether whichcomprises:

(a) dispersing an alkali metal fluoride in an anhydrous inert solventfor the ketone desscribed below, (b) cooling the dispersion to atemperature not above 35 C., (c) adding to the cooled dispersion aketone of the structure 2. A process for preparing a glycidyl etherwhich comprises:

(a) dispersing an alkali metal fluoride in an anhydrous inert solventfor the ketone described below, (b) cooling the dispersion to atemperature not above 35 C., (c) adding to the cooled dispersion aketone of the structure (d) warming the resulting reaction mixture toabout room temperature,

(e) without isolating the so-formed intermediate, adding to the reactionmixture an epihalohydrin selected from the group consisting ofepichlorohydrin, epibromohydrin, and epiiodohydrin,

(f) stirring the reaction mixture at a temperature of about 50 to 100C., and

(g) recovering the so-produced glycidyl ether having the structure 3. Aprocess for preparing a glycidyl ether which comprises:

(a) dispersing an alkali metal fluoride in an anhydrous inert solventfor the ketone described below, (b) cooling the dispersion to atemperature not above 35 C., (c) adding to the cooled dispersion aketone of the structure JJFzCI (d) warming the resulting reactionmixture to about room temperature,

(e) without isolating the so-formed intermediate, adding to the reactionmixture an epihalohydrin selected from the group consisting ofepichlorohydrin, epibromohydrin, and epiiodohydrin,

(f) stirring the reaction mixture at a temperature of about to C., and

(g) recovering the so-produced glycidyl ether having the structureReferences Cited UNITED STATES PATENTS 3/1970 Pittman et a1. 260-348 25NORMA S. MILESTONE, Primary Examiner

